Agricultural foams contain whey solids derived from milk from which cheese is manufactured. Foams of the present invention are of whey solids origin. Whey solids are recovered from whey, the aqueous solution remaining after the curds are collected for cheese manufacture. Whey solids, among other compounds, contain a high content of lactose ranging from 67 to 78.5% and protein ranging from 7.5 to 51%.
Materials from which the whey solids of this invention are obtained originate with the dairy and cheese manufacturing industries. Whey solids are avaiable in a wide range of Trade Names reflecting gradations as to physical properties, prices, composition, and method of manufacture. Whey solids may be edible or inedible (feed-grade) depending on the method of manufacture. The majority of the edible whey solids are spray dried leaving the protein content of the solids essentially undenatured. Inedible or feed-grade whey solids are predominantly roller dried and the extent of denaturation of the protein would vary with the care exercised in drying the product. The whey solids of the present invention were selected for preparation of agricultural foams because they contain an appreciable content of protein in addition to the high lactose content.
B. H. Webb described the "Utilization of Whey in Foods and Feeds" in the proceedings of the Whey Utilization Conference, University of Maryland, June 1970. From this report we learn that the protein present in whey solids is lactalbumin and the milk sugar is lactose. If during recovery the lactose is crystallized, the product is stabilized and does not readily pick up moisture and cake. Likewise, if the whey solids are manufactured by foam-spray drying, the spherical particles will be readily dispersible and will not cake. The least expensive of the whey solids products are those that are roller dried and are suitable only for animal feed.
These agricultural foams contain glues derived from collagen which is a protein constituent of animal hide and bone. Foams of the present invention are of whey solids origin to which selected concentrations of hide glues are added to improve the desired characteristics. Hide glues are derived from collagenous materials present in hide pieces and in connective tissue associated with the hide. Collagen contains a disproportionately high content of hydroxyproline and proline, respectively 14% and 15%.
The glues of this invention originate with the packing and canning industries and are principally of cattle origin. As a group, hide glues are the strongest most versatile of animal glues with respect to broad usage in industry. The glues of the present invention were selected for preparation of the foams of this invention because they are basically protein.
The National Association of Glue Manufacturers, Inc., with headquarters in New York City, has prepared a booklet bearing the title "Animal Glue in Industry," describing an excellent overall view on glues. From this piece of literature we learn that "Animal glue is an organic colloid of protein derivation which meets with constantly increasing acceptance for adhesive, sizing and coating compositions, and colloidal applications in industry. The product is the oldest type of glue . . . ."
These agricultural foams contain a viscosity-builder, the active ingredient of which is a polysaccharide of molecular weight about 1,000,000, containing D-glucose, D-mannose and D-glucuronic acid in an approximatel 3:3:1 ratio. Both edible and industrial grades of this viscosity-builder are available and these were used singly or in combination with another polysaccharide that is a straight chain, regularly branched D-mannose polymer wherein each fourth mannose unit carries a D-galactose substituent. The latter can be used with the former in any weight ratio combination of 1 to 99 or vice versa.
Surfactants usd in these foams are generally selected from a group of modified long chain alkyl sulfates wherein the alkyl component ranges from C.sub.12 to C.sub.18 in combination with an approximately equal proportion of dodecyl ether of polyethylene glycol.
The agricultural foams contain activated charcoal which is a powdered carbon characterized by a very large surface area per unit volume because of an enormous number of fine pores. Foams of the present invention are of improved foam-producing compositions made of whey solids and animal hide glues to which selected concentrations of activated charcoal are added and are designed to contribute improved methods of uniformly distributing the charcoal at selected areas to bring about detoxification of the soil. Activated charcoal is derived from cellulose, wood, peat and coals of bituminous or lower rank by heating at 900.degree.C for a brief period in air, carbon dioxide or steam to render it more porous and more efficient.
Sorptive properties of the activated charcoal result from a very large internal surface and detoxification of the soil depends on the capacity of the charcoal to absorb residual toxic herbicides and pesticides.